inksmith

Having the same issues, flashing on and off...staying on...then turning off. Couple nights ago it blew a brake line. Only been doing this for a couple of weeks, but the first time I noticed it was 3 weeks ago when I came to a normal stop and the ABS kicked in and I got the lights. Drove down the road an hour or so, stopped for fuel and they went away. But yeah, now it's a constant thing.

CORed

Hijack alert: My 2001 with just rear wheel ABS has these two lights on as well. I replaced the rear pumpkin ABS sensor but the problem persists.

Specifically, when the truck is cool... the two lights go on at start-up. After driving a bit and warming things up, if I stop and restart, they often go out and stay out. Cruise and Speedo have always worked normally whether the lights are on or off.

With 2-wheel ABS, I'm not sure what to try next. Suggestions appreciated.

Marine

I have the problem with the brake light and ABS light on. Came on when it was 100 degrees out this past July driving on the highway.
I replaced the Speed sensor on the rear-end and that did not fix it. I changed it because the scanner said the truck was going 3mph when it was parked.

Something is telling the truck that it is moving when it is not and I think this may have something to do with the ABS light. I want to look at the ABS front sensor on the wheels but have not had a chance.

Anyone else get this far?

Thanks,

CORed

Hi Mike - thank you for your service!

My two lights are still on. Replacing the rear sensor like you did did NOT fix the problem. It was worse when it was cold for me, in hot weather or after driving to warm everything up, the lights would go out after a restart.

I do NOT have front ABS, just rear so can't help you with front.

I took it to a mechanic friend of mine. He diagnosed it to the Hydraulic Control Unit. Evidently there are valves in that unit that open and close based on sensors and if a valve is stuck, the lights can come on the dash.

The HCU is $450 + labor so I haven't replaced it yet. The lights in the dash are still on today.

Marine

Hi CORed,

You are welcome.
I don't know if I have front ABS but I am pretty sure I do. Regardless, would a brake fluid flush possibly fix it if it is gummed up? I did one a couple years ago....
Thanks,

CORed

I'm not sure if the stuck actuator is in the fluid or not. I imagine it is not. Maybe someone that has broken into one of these HCUs can comment.

BTW - I grew up in Great Falls.

VADSLRAM

I can't say for sure on a 01 but my 99 gave me fits for about 2 yrs. I finally figured out it was the brake light switch. On a 99 at least the switch has about 6 connections, some are just for the ABS. That would be fine but the way the switch is "adjusted" is goofy as hell. You install the switch with the plunger held back by a clip. Once it is all set up and the pedal is at rest position you pull the clip and the plunger snaps out to touch the pedal arm. If you don't do it that way or like in my case you take the switch off to get to something behind it, the contacts aren't made correctly and the PCM thinks the brake pedal is being constantly pressed. That make it throw the ABS and brake light plus deactivate cruise control.

CORed

Good point - on mine, I still have working cruise control.

Marine

lso have working cruise control. I saw a vid on youtube about taking the controller off and looking at the circuit board. The solder on one of the joints came undone and he fixed it with a soldering iron. It is the box with the 2 electrical connections on top of the ABS unit.
Anyone else try repairing it?

Marine

I found one at the junk yard and put it on the truck and it fixed the brake light / ABS light issue. I couldn't really tell from the truck but it may have been a 1/2 ton. I still need to check the speed with a GPS to see if it is accurate.
I plan to send my original one to modulemasters to get fixed, so bringing the new used one to the dealer to get re-flashed is a moot point for me. It is however, from an '01 as well, so I am sure I am on borrowed time with it anyways.

Marine

Update on my situation; ABS and Brake light came back on. Speedo works.
I sent my original ABS Module to circuitboard medics and they said nothing is wrong with it so they are sending it back.
I'm stumped....Maybe it is the HCU....

CORed

This past spring I had my Brake HCU replaced and it fixed the issue. No more lights on the dash. A mechanic friend of mine did it.

What I also found out is there are HCUs that "seem" like they should work, but if not from a 2500 diesel, they won't. I had received one from a gas truck and after install, the lights would back on in about 1-2 minutes of driving. I took it to the dealer for a VIN reflash - which was recommended, and they confirmed the part # was not exactly the right one for my truck.

So it was returned and another one was found - I believe it was a used HCU, not sure. Anyway, that resolved the issue.

HTH

Marine

Thanks. I wonder if it is the same unit on the 2001.5 as yours was.

Marine

Is this the same as the hydro booster unit? No it is not. The HCU is located under the ABS control module.

CORed

I believe you are correct. I remember a bit more... the build date is important. Mine was built in early 2000 as a 2001. It may have contributed to the initial part issue I had. Just FYI.